1. Field
The present invention is generally related to data processing, and more specifically to retrieving data from a database.
2. Description of the Related Art
Databases are computerized information storage and retrieval systems. A relational database management system is a computer database management system (DBMS) that uses relational techniques for storing and retrieving data. The most prevalent type of database is the relational database, a tabular database in which data is defined so that it can be reorganized and accessed in a number of different ways. A distributed database is one that can be dispersed or replicated among different points in a network. An object-oriented programming database is one that is congruent with the data defined in object classes and subclasses.
Regardless of the particular architecture, in a DBMS, a requesting entity (e.g., an application or the operating system) demands access to a specified database by issuing a database access request. Such requests may include, for instance, simple catalog lookup requests or transactions and combinations of transactions that operate to read, change and add specified records in the database. These requests are made using high-level query languages such as the Structured Query Language (SQL) and application programming interfaces (API's) such as Java® Database Connectivity (JDBC). The term “query” denominates a set of commands for retrieving data from a stored database. Queries take the form of a command language, such as SQL, that lets programmers and programs select, insert, update, find the location of data, and so forth.
Any requesting entity, including applications, operating systems and, at the highest level, users, can issue queries against data in a database. Queries may be predefined (i.e., hard coded as part of an application) or may be generated in response to input (e.g., user input). Upon execution of a query against a database, a query result is returned to the requesting entity.